title: Lipoprotein-associated phospholipase A2 activity improves risk discrimination of incident coronary heart disease among women.
abstract: BACKGROUND
  This study sought to determine the relation between and discriminative capability of lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) and coronary heart disease (CHD) in a large population of disease-free women.
  
  
  METHODS
  Among participants of the Nurses' Health Study who provided a blood sample, there were 421 cases of incident myocardial infarction during 14 years of follow-up. Controls were matched to cases 2:1 using risk set sampling based on age, smoking, and blood draw date.
  
  
  RESULTS
  After conditioning on the matching factors, Lp-PLA(2) activity was significantly associated with myocardial infarction (relative risk [RR] 2.86 for extreme quartiles, 95% CI 1.98-4.12). Upon additional adjustment for lipid, inflammatory, and clinical risk factors, the RR remained statistically significant (RR 1.75, 95% CI 1.09-2.84). The discriminative capability of Lp-PLA(2) was assessed by comparing the area below the receiver operating characteristic curves for models with and without Lp-PLA(2) and by calculating the net reclassification improvement index. The addition of Lp-PLA(2) activity to a multivariable-adjusted model increased the receiver operating characteristic curves from 0.720 to 0.733 and significantly improved the net reclassification improvement index (P = .004).
  
  
  CONCLUSIONS
  Levels of Lp-PLA(2) activity were significantly associated with incident CHD among women. In addition, Lp-PLA(2) activity added significantly to CHD risk discrimination.
authors.affiliation: Department of Nutrition and Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA. ihatoum@hsph.harvard.edu
authors.forename: Ida J
authors.initials: IJ
authors.lastname: Hatoum
authors.forename: Nancy R
authors.initials: NR
authors.lastname: Cook
authors.forename: Jeanenne J
authors.initials: JJ
authors.lastname: Nelson
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: Rexrode
authors.forename: Eric B
authors.initials: EB
authors.lastname: Rimm
mesh_terms: D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase / Q000378:metabolism*; D000328:Adult; D016022:Case-Control Studies; D003327:Coronary Disease / Q000201:enzymology* / Q000453:epidemiology; D005260:Female; D006801:Humans; D008019:Life Style; D016015:Logistic Models; D008875:Middle Aged; D015999:Multivariate Analysis; D012372:ROC Curve; D018570:Risk Assessment
chemical_list: D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase